Canopy management: The balance between lodging risk and nitrogen use for spring wheat production in the Canadian Prairies

Lodging risk in spring wheat has grown with the introduction of high yielding cultivars that require high nitrogen (N) inputs to optimize grain yield and protein content. Canopy management (CM) strategies have been used to reduce lodging risk. However, the short growing season and unpredictable moisture supply may limit the use of these strategies in the Canadian Prairies. The objective of this study was to quantify the ability of agronomic practices to modify the early season crop canopy, and hence lodging risk, and to determine how these practices influence N use and final grain N yield. Split-plot field trials were established at four site-years in Manitoba to evaluate CM strategies including three plant densities, a split N fertilizer application, and the application of chlormequat chloride (CCC) on canopy size (dry matter and height at anthesis), N uptake and remobilization, lodging and stalk strength, grain yield, protein, and grain N yield on the cultivar AAC Brandon. Precipitation was low during this study (64 – 78% of long-term average) resulting in modest yields and low lodging pressure. However, low plant density, split N, and CCC applications all showed potential to reduce lodging risk without reducing grain yield or protein concentration. Split N and PGR applications increased final grain N yield by 11.2 and 2.4 %, respectively. Therefore, CM practices have potential in the Canadian Prairies to reduce lodging risk without compromising grain N, but results should be validated in higher precipitation environments and across additional cultivars and growing regions of western Canada.